The invention relates to an X-ray diagnostic system comprising a radiographic unit with an X-ray tube, which emits a fan-shaped radiation beam, with a radiation detector for receiving the radiation emerging from the radiography subject and delivering electric output signals corresponding to the received radiation profile, with means for generating a relative movement between the support device for the radiography subject, on the one hand, and the radiation beam, disposed transversely to its longitudinal direction, on the other hand, and with a measured value converter with a display unit which, from the detector output signals, determines and displays the X-ray shadow image corresponding to the range of movement.
A diagnostic X-ray system of this type is described in the U.S. Pat. No. 3,101,407. In the case of this diagnostic X-ray system, the radiographic unit, comprised of the X-ray tube and radiation detector, is displaced in the longitudinal direction of the support device such that an X-ray shadow image can be constructed from the output signals of the radiation detector. The radiation detector is formed of an array of individual detectors. An X-ray fluoroscopy is possible only incompletely with the known diagnostic X-ray system, since a very rapid back-and-forth movement of the radiographic unit is necessary for this purpose, which is difficult to realize in practice. It is, indeed, conceivable to dispense with the detector movement during the scanning of the radiography subject if the radiation detector is designed to be long enough in the longitudinal direction of the support device so that it can detect the X-radiation emerging from the radiography subject without mechanical movement over the entire range to be scanned; however, in this case, a mechanical movement of a secondary radiation diaphragm (important for the purpose of stray radiation suppression) between the radiography subject and the radiation receiver is necessary, which leaves open a slot for the fan-shaped X-ray beam, and which is so moved with the X-ray beam that the X-ray beam, in every position, can pass through the slot and strike the radiation detector.